I believe the authors of these lexicons have more knowledge on this than you do.
Thayer's lexicon: "used of only sons or daughters (viewed in relation to their parents)."
Friberg's Anlex; "(2) as a child born in a unique way; (a) used of God's Son Jesus only, only begotten;"
Liddell-Scott lexicon: "only-begotten"
BAGD lexicon: "only...of children"
Abbot-Smith lexicon: "only, only begotten"
TDNT: "'of sole descent,' i.e., without brothers or sisters."
Surely you are not using these sources to suggest that μονογενης only means "only begotten"???
I am sure I have just missed something, but looking at Van's charge and your reply, that is how it seems. Perhaps your point is that the word "can " mean "only begotten".
BDAG
1...to being the only one of its kind within a specific relationship, one and only, only
2...to being the only one of its kind or class, unique
TDNT
More generally it means 'unique' or 'incomparable.'
I don't have my Frieberg Anlex with me...so I can't check it. But the fact that the number "2" is used in your definition, there is others.
Lowd Nida
pertaining to what is unique in the sense of being the only one of the same kind or class - unique, only.
EDNT
only (one of its kind), unique*
Barclay Newman
only, unique
Sent from my SM-G965U using Tapatalk